The Leatherback Sea Turtle holds the title as the largest turtle. This ancient reptile captivates with its unique adaptations and impressive size.
The Leatherback Sea Turtle
The Leatherback Sea Turtle (Dermochelys coriacea) is the largest turtle globally and among the largest living reptiles. Adults typically measure around 6.5 feet (2 meters) in length and can weigh up to 2,000 pounds (900 kg). The largest recorded individual was nearly 10 feet (3.05 meters) long and weighed 2,019 pounds (916 kg).
Unlike other sea turtles, the leatherback lacks a hard, bony shell. Its carapace consists of tough, rubbery skin covering a mosaic of small, interlocking dermal bones. This distinctive leathery shell features seven prominent longitudinal ridges, giving it a streamlined, hydrodynamic shape. Its powerful, elongated front flippers, which lack claws, are adapted for efficient long-distance swimming.
Leatherbacks exhibit gigantothermy, allowing them to maintain a body temperature warmer than the surrounding water. Their substantial body mass and thick layer of insulating subcutaneous fat help retain metabolic heat. A specialized countercurrent heat exchange system in their circulatory network minimizes heat loss from their extremities, enabling them to thrive in colder waters.
Oceanic Wanderers: Habitat and Behavior
Leatherback Sea Turtles boast the widest global distribution of any reptile, inhabiting tropical, temperate, and even subpolar waters across the Atlantic, Pacific, and Indian Oceans. They venture as far north as Alaska and Norway and as far south as New Zealand. These turtles are primarily pelagic, meaning they spend most of their lives in the open ocean, only approaching coastal areas for nesting.
They are exceptional divers, capable of plunging to depths of nearly 4,000 feet (1,280 meters), deeper than any other turtle species, and can remain submerged for up to 85 minutes. Their diet consists almost exclusively of soft-bodied prey, primarily jellyfish and salps, which they pursue by diving deeper during the day when these prey migrate vertically. Their mouths are adapted with pointed, tooth-like cusps and backward-pointing spines to capture and retain gelatinous prey.
Leatherbacks undertake extensive migrations, traveling thousands of miles between their foraging grounds and nesting beaches. Some individuals cover distances averaging 3,700 miles each way annually. Female leatherbacks return to tropical or subtropical nesting beaches every two to four years to lay their clutches of eggs.
Conservation Status
Leatherback Sea Turtle populations face significant challenges. The species is globally listed as “Vulnerable” by the IUCN Red List of Threatened Species. Several subpopulations, particularly in the Pacific and Southwest Atlantic, are classified as “Critically Endangered,” while the Northwest Atlantic subpopulation is listed as “Endangered.”
Plastic pollution is a major threat, as leatherbacks often mistake plastic bags for their primary food source, jellyfish, leading to fatal ingestion and blockages. Incidental capture in fishing gear, known as bycatch, poses a severe risk, with thousands of turtles becoming entangled in longlines, gillnets, and trawls each year. Habitat loss and degradation of nesting beaches due to coastal development, erosion, and artificial lighting also impact their survival.
Climate change is a growing concern, affecting nesting sites and potentially skewing the sex ratios of hatchlings. Conservation efforts focus on protecting nesting beaches, reducing bycatch through improved fishing practices, and fostering international collaboration to safeguard these migratory animals.